BMI – Is it fit for purpose? My Opinion.

BMI – or Body Mass Index – is the “go to” measurement of if you are at a healthy weight for your height. There are countless calculators out there that will take your weight and your height perform some fancy equation and come back with your BMI score.

Is it fit for purpose?

Personally – I don’t think so. It’s outdated. BMI came about in the 1950’s and body shape and lifestyles have changed significantly since then.

However it is still the measuring stick that the health care profession like to use. Mainly as there isn’t anything better out there that they can all agree upon.

18.5 to 24.9

What do those numbers mean? Basically those are the BMI scores that if you fall between that is considered “healthy”. Anything over 25 is considered as “overweight” (and then “Obese” and “Morbidly Obese”), and anything below 18.49 is considered “underweight”. There are some variations to take into account gender and body type but these seem to be less used/taken into account.

That is, in my opinion, one of the flaws with BMI – it’s generally a flat one chart suits all approach for a lot of health care professionals.

But being healthy is good surely?

Can’t argue with you there. We all want to be healthy. But does our health depend on if we have a BMI of between 18.5 and 24.9? It’s a good yard stick and something to aim for but I’m not sure that should be our focus. More importantly we want to look good and feel good in ourselves.  That feel good in ourselves factor should not be defined by a number – 25 and above – you’re not healthy, 25 and below and you are.

The picture above shows a guy who weighs a shade under 12 stone and who is 5’10 in height. His BMI is roughly 24.8 and therefore only just in the “healthy” range. He has a 32inch waist (almost into a 30inch waist).  With that BMI score – it could be said that he could do with loosing a little more weight. Looking at that photo – personally, I’d say he needed to put a few more pounds on.

How do I know that information and how do I dare say that he needed to put weight on? That photo is me in 2011 having lost just shy of 16stone with Slimming World and being named in 5th place at that years (national) “Greatest Loser” competition. Actually I was a little below target at the time and did put a little back on but in hindsight probably needed to have stopped about half a stone sooner. But that’s hindsight for you.

A lot of professional sports people would register as being “overweight” based purely on their BMI. BMI makes little/no provision for activity or musculature or body shape or gender (Though there have been a few suggestions for doing so).

BMI – my viewpoint – in summary

A healthy BMI is a good yardstick to aim for when loosing weight. But it isn’t the be all and end all. Have a “healthy” BMI score as a target but just as with setting a final weight – don’t get too hung up on the numbers. Listen to your body – it will know when to stop – and if that’s a slightly higher than “healthy” BMI or a few pounds away from where you thought you wanted to be – be happy. There’s nothing to say that you can’t proceed later on to try that final push.

The obvious exception here – If your Doctor says to loose X amount for medical reasons – follow that advice. Maybe question it – but they are the people who are paid to look after you – so always always heed their advice.


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